News Release Archive

Reclamation awards $3.4 Million contract for new turbine runner at Hoover Dam

Will ensure power generation efficiency over wide range of lake elevations

Media Contact: Robert Walsh , (702) 293-8421 , rwalsh@usbr.gov
Colleen Dwyer , cdwyer@usbr.gov

For Release: April 16, 2010

Commissioner of Reclamation Michael L. Connor today announced the award of a $3,404,380 contract to Andritz Hydro Corporation of Charlotte, North Carolina, for the design and manufacture of a new "wide-head" turbine runner for generating unit N-8 at the Hoover Dam powerplant. The "turbine runner" is the water wheel portion of the generating unit that drives the generator. "N-8" is the designation for the number 8 unit in the Nevada wing of the powerplant.

The new runner is scheduled to be delivered to the dam in February 2012 for installation by Reclamation. If it performs as anticipated, Reclamation may exercise a contract option for additional runners for generating units N-6, A-1 (the number 1 unit in the Arizona wing of the powerplant), and N-5. If the contract option is exercised, the total investment in the new turbines will be approximately $11.56 million. If ordered, the additional runners would arrive at the dam in November 2013, 2014 and 2015, respectively.

"The new turbines will allow the generating units to operate more efficiently over a wider range of lake levels (or "head") than the existing turbines do," Connor said. "That will enable Hoover Dam to generate power more efficiently as the water level behind the dam fluctuates between low and high elevations." There are 17 commercial generators in the Hoover Dam powerplant - nine in the Arizona wing and eight in the Nevada wing. Since 1947, an average of about 4.4 billion kilowatt-hours of energy has been generated at the dam annually, or enough to supply about 400,000 U.S. households with all of their electricity needs for one full year. The energy is marketed to customers in southern California, southern Nevada and Arizona under 30-year contracts signed in 1987.

The existing turbines at Hoover Dam are designed, in general, to operate over a higher range of lake levels. At very low lake levels, operation of existing turbines becomes rough and inefficient.

For example, the existing N-8 turbine is designed to operate when Lake Mead is as low as elevation 1050 feet above mean sea level (msl), but will operate more roughly below that level. The new N-8 turbine will be designed to operate smoothly and efficiently at lake levels down to elevation 1000 msl. Lake Mead is currently at elevation 1099 feet msl, or about 120 feet below the full operating level. The water level has dropped as Hoover Dam has continued to provide consistent water deliveries to Colorado River water users in the Lower Colorado River Basin during the worst drought on record in the basin since the early 1900's.

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